Refrigeration



Sept. 29, 1942.

' 2 Sheets-Sheet 1 .!iiiiiiiiiiiiiiiii.iil

1 .'.'.'.i. 5 iiiiiii iiiiiiiiiiiiiii INVENTOR v 'ea yeAuBmce ATTORNEY wpghzs, 1942. P G. A BRACE I. REFRIGERATION Filed July 20, 1958" 2Sheets-Sheet 2- //////////////////////////fl////)/// /////////fl"INVEIQTOR Geozye A. Brae 6 BY A Y ATTORNEY Patented Sept. 29, I942REFRIGERATION George Ac Brace, 11h, alsignorto The Hoover Company, NorthCanton, Ohio, a corporation of Ohio Application July 20, use. Serial No.220,191

- 25 Claims. (oi. se-s) This invention relates to the art ofrefrigeration and more particularly to a novel absorption refrigeratingsystem.

According to the presen invention there is provided a refrigeratingsystem of the absorption type which includes a pair of evaporatorsections connected in parallel into an izing medium circuit and adaptedto perform different flmctions. One evaporator section is adapted to beplaced in heat transfer relationship with a body of water in order tofreeze ice V blocks within the body of water periodically. Means areprovided to permit periodic discharge of liquid refrigerant" and inertgas into the ice freezing evaporator and to discontinue such dischargeof inert gas and liquid refrigerant for a period of time in order topermit previously formed ice blocks to melt free of the walls of thewater container. The other evaporator section is arranged to refrigeratealow temperature refrigerating chamber.

his a further object of the invention to provide an absorptionrefrigerating system in which the production of ice is regulated by acontrol.

mechanism which operates to divert certain fluids in the system fromtheir normal paths of flow, to alter the pressure at which certainfluids are circulated, and to prevent the flow of certain fluids in thesystem. I

It is a further object of the invention to provide a refrigeratingsystem in which the produc-' tion of ice is regulated by diverting andregulating the flow of fluids within the system without introducing anymoving parts'into the system to accomplish these results.

It is another object of the invention to provide a refrigerating systemof the three-fluid type in which liquid refrigerant generated in thesystem is stored in a suitable receptacle and is utilized to preventflow of inert gas through an ice freezing evaporator during a periodduring which it is desired to render the evaporator inoperative in orderto free previously formed ice blocks.

inert pressure equal- I refrigerating system em r g the invention and inwhich the evaporator is shown in perspective.

Figure 2 is a transverse sectional elevational view of theevaporator-shown in Figure 1 and associated'with a suitable ice freezingwater tank and a suitable low temperature insulated refrigeratingcompartment.

Figure 3 is a detailed view drawn to an enlarged scale illustrating thecontrol mechanism.

Referring now to the drawings and first to Figure 1 thereof, there isillustrated athree-fiuid' absorption refrigerating system comprising aboiler B. an analyzer D, an air-cooled rectifier R, a' tubularair-cooledeondense'r C, an evaporator E, a gas heat exchanger H, atubular aircooled absorber A, a liquid heat exchanger L, a

gas burner G for heating the boiler 23, and a circulating fan F which isdriven by an electrical motor M. The above described elements aresuitably interconnected by various conduits to form a plurality of gasand liquid circuits to which reference will be made in moredetailhereinafter.

The above described refrigerating system will be charged with a suitablerefrigerant, such as ammonia, a suitable absorbent, such as water, and asuitable pressure equalizing medium, such as nitrogen.

The application of heat to the boilerB liberates refrigerant vapor fromthe strong solution It is a further object of the invention to provide arefrigerating system having a plurality of evaporators connectedtherein, one of which opcrates periodically and the other of whichoperates substantially continuously.

It is another object of the invention to provide a three-fluidabsorption refrigerating system of the type utilizing a power drivencirculator to propel a pressure equalizing medium through certainportions of the system which is controlled by varying the speed of thepressure equalizing medium circulator.

Other and further objects of the invention will become apparent as thedescription proceeds when taken in connection with the accompanyingdrawings in which:

therein contained, which vapor then passes upwardly through the analyzerD in counterflow to strong solution flowing downwardly therethrough.Further refrigerant vapor is generated from the strong solution in theanalyzer by the heat of condensation of vapor of absorption solutiongenerated in the boiler. The refrigerant vapor is conveyed from theupper portion of the analyzer to the upper portion of the condenser C bya conduit 4 I which includes the rectifier R. Any vapor of absorptionsolution which may pass through the analyzer is condensed in therectifier and is returned into the boiler system through the conduit II.

The refrigerant vapors supplied to the con- Q denser is liquifiedbfheatexchange with cooling air and is conveyed from the condenser intothe evaporator E through a conduit [2.

The exact operation and description of the evaporator will be describedin detail hereinafter,

for the present it is suflicient to say that the liquid refrigerantdischarged into the evaporator E evaporates into a stream of pressureequalizing Figure 1 is a diagrammatic view illustrating a no mediumflowing therethrough to produce refrigeration. The rich pressure.equalizing medium formed in the evaporator E is conveyed therefromthrough a conduit. ii, the inner path of the gas heat exchanger H, and aconduit l6, which discharges into the bottom portion of the tubularinclined air-cooled absorber.A. The pressure equalizing medium flowsupwardly of the gas heat exchanger H sorber vessel. The lean pressureequalizing medium formedin the absorber is conveyed from the upperportion thereof into the suction inlet of the circulating fan F by aconduit l3. The pressure equalizing medium is placed under pressure bythe fan and is discharged therefrom througha conduit 23 into the outerpath of the gas heat exchanger H. The pressure equalizing medium is thenconveyed from the outer path into the evaporator E by a conduit 2|.

The lean solution formed in the boiler B by the generation ofrefrigerant vapor is drained therefrom through a conduit 23, the innerpath of the liquid heat exchanger L, and a conduit 24 which opens intothe upper portion of the absorber A. It is apparent that the upperportionv of the absorber A is at an elevation considerably above theliquid level prevailing in the boileranalyzer system wherefore somemeans must be provided in order to elevate the weak solution into theabsorber. For this purpose, a small bleed-off conduit 25 is connectedbetween the discharge conduit 20 of the circulating fan F and the weaksolution conduit 24 below the liquid level normally prevailing in theboiler-analyzer system whereby the weak solution is elevated into theabsorber by gas lift action. The weak solution flows downwardly throughthe absorber by gravity in counterflow relationship to the rich pressureequalizing medium refrigerant vapor mixture conveyed into the bottomportion of the absorber from the evaporator as previously described. Thestrong solution formed in the absorber is drained from the bottomportion thereof through a conduit 21 into the outer path of the liquidheat exchanger L from which the strong solution isthen conveyed to theupper portion of the analyzer'D by a conduit 23.

The evaporator comprises an upper U-shaped ice freezing conduit 33 and alower W-shaped fast-freezing regfrigerating conduit 32 which isconnected to the inert gas. supply and ret pipes 21 and I5,respectively.

The inert gas supply conduit 2i opens into a gas blocking and liquidrefrigerant storage chamber 34 which is divided into a pair of chambersby a partition wall 35 which extends from the top wall of the chamber 34to a point slightly spaced above the bottom thereof. The conduit 2|opens into the chamber 34 at the top thereof and on the left hand sideof the partition 35, as viewed in Figure 1. A conduit 31 connects oneleg of the evaporator conduit 30 to the top portion of the chamber 34 onthe right hand side of the partition 35, as viewed in Figure 1. Theother leg of the U-shaped conduit 30 connects directly in the inert gasreturn conduit l5.

The liquid refrigerant discharge conduit l2 opens into the conduit 30adjacent its point of connection with the gas supply conduit 31. A gaslift pump conduit 39 is connected between the bottom portion of theconduit l2 adjacent the condenser and the vessel 34 on the right handduit as below the level of its point of connection to the liquid conduit12. A syphon conduit 4| is connected to the conduit l2 between the pointof connection of the gas lift pump and the evaporator thereto. Thesyphon conduit 4| extends upwardly to a level well above thejbottom ofthe vessel 34 and then turns downwardly within the vessel 34 onthe lefthand side of the partition 33. The free end of the syphon conduit 4|extends'to a level adjacent the bottom portion of the vessel 34 andbelow the bottom portion of the partition 35.

A .drain conduit 44 is connected to the conduit 33 adjacent the gasoutlet portion thereof and opens into the gas inlet portion of theconduit 32 after extending therebelow to form a U-shaped liquid seal. Asmall dam 45 is mounted within the gas outlet portion of the conduit 30to prevent liquid refrigerant from flowing into the conduit II.

Referring now to Figures 1 and 2, the functions of the variousevaporator sections will be described in connection with certain otherstructures of the apparatus. Each leg of the U- shaped conduit 33 isprovided with a plurality of inclined spaced freezing pads 40 which areadapted to receive the tapered bottom portion 43 of a water container33. The evaporator section portion of the chamber 52 to underlie thebottom portion of the tank 50 and the U-shaped evaporator 33.

The gas burner G is supplied with fuel from any suitable source by aconduit 61 which includes a valve it operated by a solenoid-.8. The gasburner G is preferably of the type having a suitable safety cut-offmechanism incorporated therein which will discontinue all supply of fuelthereto in the event of complete flame failure at the burner. A smallby-pass conduit 53 is provided around the valve 56 in order to obtain asmall igniting or pilot flame on the burner G during periods of closureof the valve 56.

side of the partition 35. The conduit 39 includes the. valve 5i.

Electrical energy is supplied to the apparatus.

from a-suitable source of supply through a pair of wires 60 and 6|. Thewire 3| connects directly to the circulating motor M and a wire 82 isconnected between the wire ii and the solenoids for The wire 30 connectsdirectly to one terminal of a suitable thermostatic switch mechanism 64.The mechanism 64 isillustrated diagrammatically herein; it may be anysuitable or desired form of thermostatic refrigerating control switchmechanism which is adapted to be mounted within a refrigeratingcompartment to respond to the temperature condition of that compartment.The other terminal of the control mechanism 64 is connected to a wire 65which connects to a wire 61 running to the solenoid S. One terminal of athermostatic switch mechanism indicated generally at 10 and to bedescribed more fully hereinafter is also directly connected to the wire31. The. other terminal of the thermostatic switch mechanism 13 isconnected by a wire H to a wire 12 which connects directly to thecircumostatic element 83.

lating motor M. A suitable element 13 is connected between the wires 41and 12 in parallel relationship with the thermostatic switch Thethermostatic switch ll comprises a housing 8| constructed of insulatingmaterial and fastened to any suitable portion'of the evaporator conduit30. As illustrated in Figure 1, the housing 4| is shown as being mountedin the bight portion of the U-shaped conduit 34 but any other suitableportion of that conduit may be utilized for mounting the housing ifdesired. Within the housing 8| a bimetallic thermostatic element 83 thetemperature of the conduit 30 will drop to.

is rigidly attached at one end to the conduit 34 the circuit betweenthose wires and thereby toshort circuit the resistance element IS.

The operation of this invention is as follows: Assuming that theapparatus has been inoperative and that the refrigerating chamber has 1reached a temperature above that for which the thermostatic controlmechanism 64 is set, the thermostatic control 64 will be'operated toenergize the circulating motor M and the solenoid S to open the valve 58to circulate the inert gas and to supply fuel to the burner G togenerate refrigerant vapor. Refrigerant vapor will then be generated inthe boiler, liquifled in the condenser and discharged through the'conduit l2 into the evaporator conduit ll. The inert gas will becirculated by'the fan F and will be discharged into the conduit 2|. Asmall portion of the gas will flow through the conduit 32, which isconsiderably smaler in diameter than the conduit 3|, and may be providedwith a restriction, if deiustifled by reason of the fact that the heavyinsulation on the small compartment" makes the refrigerating load onthatcompartment relatively low. under all conditions, even though theinterior of the chamber 52 is maintained at a very low temperature whileit is substantially full oi foodstuffs or of material to befrozen. a

The above described operation continues until ice, blocks have formedon, those portions of the inclined bottom 49 of the tank so in directthermal contact with the freezing pads 48. When such ice blocks form toa predetermined thickness,

a very low value which will their cause the thermostat 43 to flex in aclockwise direction, as viewed in Figure 3, to close the circuit betweenthe wires 61 and H. When this occurs, the resistance element 13 isshort-circuited out of the motor circuit and the motor operates at itsmaximum speed. When the motor is operating at maximum speed, the fandevelopssuiilcient pressure to operate the gas lift pump 39 and allliquid refrigerant flowing through the conduit i2 is elevated into thechamber 34. The increased fan pressure tends to cause an increase in therate of flow of-absorption solution due to'the greater quantity of gasdischarged from the bleed conduit 25. If this increase approachesobjectionable proportions, any suitable form of flow regulating means}such as that disclosed in my copending application Serial No. 220,195,filed July 20, 1938, now Patent No. 2,264,292, may be incorporated inthe solution circuit.

The liquid refrigerant discharged through the conduit 39 into thechamber 34 very quickly seals the bottom portion of that tank inconjunction with the partition 35 and prevents the discharge of inertgasinto the conduit 31 and hence into the evaporator conduit 30. Underthese conditions neither liquid refrigerant nor inert gas is beingsupplied to the conduit 30 and previously formed ice blocks melt free ofthe bottom wall of the tank 48 and floatto the surface of the watertherein contained where they remain until sired, to limit the flow ofgas therethrough. The

remainder of the inert gas will flow through the conduit 2|, the chamber34, the conduit 31, and the U-shaped conduit 30 from which it will bereturned to the conduit I5. I Due to the fact that the evaporatorconduit 30 is relatively warm,the thermostatic element 83 within theswitch housing 4| will be flexed in a counterclockwise direction, asviewed in Figure 3, to open the circuit between the wires 61 and l Ithereby placing the rei sistance element 13 in series with thecirculating motor M with the result that the speed of the motor will besomething less than the maximum.

Under these conditions, the circulating fan F does not developsuflicient pressure to operate the gas lift pump 39 and allliquidrefrigerant formed in the condenser flows directly through theconduit |2 into the evaporator conduit at through which it flows bygravity in parallel relationship with the inert gas supplied through theconduit 31 as it is evaporating into the inert gas to pro-.

duce refrigeration. Any liquid refrigerant not evaporated in the conduit30 flows through the U-shaped trap conduit 44 into the evaporatorsection 32 through which the liquid refrigerant flows in parallelwith'the inert gas stream to refrigerate the insulated compartment 52.

fsyphon 4| as explained below.

The greatest refrigerating load occurs on the conduit 30 and only asmall portion of the liquid refrigerant ever reaches the conduit 32.This is 75 ladled out for use. This operation will continue until thetemperature of the conduit 30 again reaches a sufliciently high valuetoactuate the thermostat 83 to open the circuit between the wires 61 and1| to again slow down the motor 'by inserting the resistor 13 in seriestherewith.

During the period when the liquid refrigerant is collecting in the tank34 there will be no refrigeration produced in the evaporator section 32except that produced by liquid refrigerant present in the evaporator 30when the inert gas supply thereto was cut oil, by reason of any liquidrefrigerant which may flow through the conduit I2 without being divertedinto the gas lift pump 39 and by any liquid which may flow through theThe chamber 34 is so proportioned that the syphon 4| will always becomeactive at least shortly before the conduit 30 reaches a temperature highenough to cause the thermostat 43 to open the circuit between the wires61 and II. Qnce the syphon 4| has become active, it will syphon outsubstantially all the liquid refrigerant in the compartment 34 into theliquid refrigerant supply line |2 leading to the evaporator conduit 30.However, the capacity of the syphon 4| is substantially equal to but notgreater than the capacity of the gas lift pump "so that the syphon 4| isnever able to lower the level of the liquid refrigerant in thecompartment 34 an amount suillcient to permit inert gas -by the syphonll during the high speed cycle of the circulating motor simply flowsthrough the evaporator section 3! and the conduit ll into thefast-freezing chamber refrigerating coil 32 where it evaporates into theinert gas stream flowing through that coil to produce refrigeration.

After the control mechanism has operated to decrease the speed of thecirculating motor, the liquid refrigerant flows directly through theconduit l2 into the evaporator section 3| as before, but it is augmentedby a stream of liquid refrigerant discharging through the syphon conduitll from the compartment 84. However, refrigeration is not produced inthe ice freezing conduit 30 until the syphon ll has emptied thecompartment 34 of a quantity of refrigerant sufflcient to permit inertgas to flow therethrough. Liquid refrigerant discharging through theconduits II and i2 into the evaporator 30 prior to supply of inert gasto the evaporator ll is ultimately discharged-through the conduit 44into the fast-freezing evaporator 32. The capacity of the tank 34 is notlarge wherefore the syphon fast-freezing coil 32 spreads throughout thelength thereof, which is extensive as shown, and

slowly evaporates into the inert gas stream flowing through that coil.

The above described cycles of operation continue so long as thetemperature within the main storage compartment of the refrigeratorremains above the value for which the thermostatic control mechanism 64is set to de-energize the refrigerating system. As long as therefrigerating system is operative the air within the main refrigeratingstorage compartment is refrigerated by flowing over the extensivesurface of the tank SI and over the freezing coil ll. Due to the factthat the coil II is only periodically operative and also because of thefact that the temperature of the exposed walls of the water tank neverreach a temperature below the freezing point of water, there is verylittle frost collection on the evaporator. The small amount offrost-which does collect on the coil 30 at each cycle thereof is meltedoff and flows into the receptacle during the ice melting period of therefrigerator. This serves to maintain the humidity within therefrigerating compartment at a high value which effectively increasesthe food preserving qualities of the refrigerating system.

The particular control herein disclosed automatically regulates theproduction of ice to sea-'- sonal demand therefore for the followingreasons. During periods of warm weather when the demand for ice isgreatest the loss of heat from the principal refrigerated compartmentwill be accelerated which will cause the control mechanism 64 to cyclethe refrigerating apparatus more frequently and will thereby produce alarge quantity of ice. On the other hand during periods of cool weatherwhen the demand for ice is at a minimum, the loss of heat through thewalls of the refrigerating cabinet will also be at a minimum which willautomatically decrease the active periods of the refrigerating apparatusand hence the production of ice. 7

The above described apparatus is particularly advantageous by reason ofthe fact that it may be mounted in any desired type of refrigeratorcabinet and will automatically produce a large quantity of ice blocksfreely-floating in a body of water whereby any desired number of suchblocks may conveniently be removed from the refrigerating apparatussimply by ladling them out of the body of water. In addition to theprovision of means for freezing ice blocks and for cooling therefrigerating chamber, a low temperature insulated freezing compartmentis provided.

The apparatus is particularly efllcient by reason of the fact that theultimate destination of the liquid refrigerant is governed by the speedof the fan for circulating the pressure equalizing medium which in turnis thermostatically controlled by a mechanism entirely without therefrigerating system, whereby complete control of the flow of fluidswithin the system is achieved without the intervention of moving parts.Additionally, the liquid refrigerant is utilized to allow or prevent theflow of inert gas through certain portions of the evaporator whereby theproduction of refrigeration within the ice freezing evaporator sectionis impossible during periods of operation of the gas lift pump 30 byreason of the fact that liquid refrigerant will not evaporate in theconduit ll unless an inert gas is flowing therethrough,

While I have illustrated and described a particular embodiment of theinvention in detail, the invention is not to be limited thereto but maybe embodied in other constructional forms and variations withoutdeparting from the spirit of the invention or the scope of the appendedclaims.- I

I claim: 1. Refrigerating apparatus comprising a cooling unit, means forsupplying a cooling medium to said cooling unit, means forpropelling apressure equalizing medium through said cooling unit, refrigerationdemand responsive means for diverting cooling medium flowing to saidcooling unit into a storage vessel in the path of flow of the pressureequalizing medium, means in said vessel adapted to cooperate withcooling medium supplied thereto to block the flow of pressure equalizingmedium to said cooling unit, and a syphon connected to drain the coolingmedium from said vessel when the liquid level therein reaches apredetermined value.

2. Refrigerating apparatus comprising an evaporator, a liquidrefrigerant supply means opening into said evaporator, means forsupplying a pressure equalizing medium to said evaporator, a liquidrefrigerant storage and gas blocking vessel interposed in said pressureequalizing medium supply means, a temperature responsive means operativeto divert liquid refrigerant from the said liquid refrigerant supplymeans into said vessel in response to a predetermined temperaturecondition of said evaporator, means within said vessel adapted tocooperate with liquid refrigerant supplied thereto to block the flow ofinert gas therethrough, and a syphon connected to discharge liquidrefrigerant from said vessel period' ed to said cooling unit,teinparature responsive means for intermittently storing liquidrefrigerant in a storage vessel, and means for flowing liquidrefrigerant from said storage vessel into.

said cooling unit after a'predetermined collecting 4. Refrigeratingapparatus comprising an evaporator including an ice freezing section anda compartment cooling section, means for supplying inert gas to each ofsaid sections, means for supplying liquid refrigerant to said icefreezing section, means for conveying unevaporated refrigerant from saidice freezing section into said cooling section, a liquid gas seal devicein the inert gas supply means for said ice freezing evaporator, meansfor divertingthe liquid 're- I frigerant from said supply means intosaid gas seal device, means for syphoning liquid refrigerant from saidgas seal device into said ice freezing evaporator section, and controlmeans for regulating said diversion means.

5. Absorption refrigeration apparatus comprising a boiler, an absorber,a plurality of evaporating elements, power driven means for propellingapressure equalizing medium through a circuit including said absorber andsaid evaporating elements, means for liquefying refrigerant A vaporgenerated in theboiler, means for supply ing such liquid refrigerant toone of said evaporating elements, means for draining unevaporatedrefrigerant from said one evaporating element into another evaporatingelement, a liquid operated blocking device for preventing the fiow ofpressure equalizing medium through said first mentioned evaporatingelement, a gas lift pump operated by pressure equalizing medium suppliedfrom said circuit for diverting liquid refrigerant from said supplymeans into said blocking device,

means for draining liquid refrigerant from said blocking device intosaid first mentioned evaporating element, and means for controlling theoperation of said gas lift pump.

6. Absorption refrigeration apparatus comprisinga boiler, anabsorber, aplurality of evaporating elements, power driven means for propelling apressure equalizing medium through a circuit including said absorber andsaid evaporating elements, means for liquefying refrigerant vaporgenerated in the boiler, means for supplying such liquid refrigerant toone of said evaporating elements, means, for draining unevaporatedrefrigerant from said one evaporating element into another evaporatingelement, a liquid operated blocking device for preventing the flow ofpressure equalizing medium through said first mentioned evaporatingelement, a gas lift pump operated by pressure equalizing meplyingsuchliquid refrigerant to one of said evaporating elements, means fordraining unevaporated refrigerant from said one evaporating element intoanother evaporating element, a liquid operated blocking device forpreventing the flow of pressure mediumthrough said first mentionedevaporating element, a gas lift pump operated by pressure equalizingmedium supplied from said circuit for diverting liquid refrigerant fromsaid supply means into said blocking device, means for draining liquidrefrigerant from said blocking device into said first mentionedevaporating element, and means responsive to the temperature of saidfirst mentioned evaporating element-for varying thepressure at whichsaid power driven means circulates the pressure medium to render saidgas lift'pump operative or inoperative in response to refrigerationdemands, said means for draining liquid from said blocking devicecomprising a syphon having a capacity not greater than the capacity ofsaid gas lift pump and arranged to become operative when the liquidlevelin said blocking device reaches a predetermined value and to removesumcient liquid from said blocking device ,to permit the pressureequalizing medium to fiow therethrough.

8. Absorption refrigeration apparatus comprising-a boiler, an absorber,'a plurality of evaporating elements, power driven means for propellinga pressure equalizing medium through a circuit including said absorberand said evaporating elements, means for liquefying refrigerant vaporgenerated in the boiler, means for supplying such liquid refrigerant toone of said evaporating elements, means for draining unevaporatedrefrigerant from said one evaporating element intoanother evaporatingelement, said first mentioned evaporating element having a plurality ofspaced heat conductors thereon, a water tank resting on said heatconductors, a liquid operated blocking device for preventing the fiow ofpressure equalizing medium through said first mentioned evaporatingelement, a gaslift pump operated by pressure equalizing medium suppliedfrom said circuit for diverting liquid refrigerant from said supplymeans into said blocking device,

means for draining liquid refrigerant from said blocking device intosaid first mentioned evaporating element, means for supplying electricalenergy to said power driven means, a resistance element in series withsaid powerdriven means adapted to reduce the speed thereof to a valuesuch that said power-driven means does not dedium supplied from saidcircuit for diverting liquid refrigerant from said supply means intosaid blocking device, means for draining liquid refrigerant from saidblocking device into said first mentioned evaporating element, and meansresponsive to the temperature of said first mentioned evaporatingelement for varying the pressure at which said power driven meanscirculates the pressure equalizing medium to render said gas lift pumpoperative or inoperative in response a to refrigeration demands.

'7. Absorption refrigeration apparatus comprising a boiler, an absorber,a plurality of evaporating elements, power driven means for propelling'apressure equalizing medium through a circuit including said absorberand said evaporating elements, means for liquefying refrigerant vaporgenerated in the boiler, means for supvelop sufiicient pressure, in saidpressure equalizing medium to operate said gas lift pump, a thermostaticswitch connected in parallel with said resistance element adapted torespond to the temperature of said first mentioned evaporating element,,and means responsive to the formation of ice blocks of a predeterminedthickness within those portions of said water tank resting on saidheatconductorsfor increasing the pressure at which the pressureequalizing medium is supplied to said gas lift pump for rendering saidpump operative and for decreasing the pressure at which the pressureequalizing medium is supplied to said pump to render the sameinoperative when previouslyuormed ice blocks have melted free of; thoseportions of said water tank in heat exchange relationship with said heatconductors. a

9. Absorption refrigeration apparatus comprising a boiler, an absorber,a plurality of evaporating elemen f, power driven means for propelling apressure equalizing medium through a circuit including said absorberandsaid evaporating elements, means for liquefying refrigerant vaporgenerated in the boiler, means for supplying such liquid refrigerant toone of said evaporating elements, means for draining unevaporatedrefrigerant from said one evaporating element into another evaporatingelement, said first mentioned evaporating element having a plurality ofspaced heat conductors thereon, a water tank resting on said heatconductors, an insulated low temperature refrigerating chamber in heatexchange relationship with said second mentioned evaporating section, aliquid operated blocking device for preventing the flow of pressureequalizing medium through said first mentioned evaporating element, agas lift pump operated by pressure equalizing medium supplied from saidcircuit for diverting liquid refrigerant from said supply means intosaid blocking device, means for draining liquid refrigerant from saidblocking device into said first mentioned evaporating element, and meansresponsive to the temperature of Said first mentioned evaporatingelement for varying the pressure at which said power driven meanscirculates the pressure equalizing medium to render said gas lift pumpoperative or inoperative in response to refrigeration demands.

10. Refrigerating apparatus comprising an ice freezing evaporator, achamber cooling evaporator, means for propelling a pressure equalizingmedium through said evaporators, means connecting said evaporators tosaid propelling means in parallel relationship, means for supplyingliquid refrigerant to said evaporators, and means for discontinuing thesupply of liquid refrigerant and pressure equalizing medium to said icefreezing evaporator without discontinuing the circulation of pressureequalizing medium through said chamber cooling evaporator.

11. Refrigerating apparatus comprising an ice freezing evaporator, achamber cooling evaporator, means for propelling a pressure equalizingmedium through said evaporators, means connecting said evaporators tosaid propelling means in parallel relationship, the arrangement beingsuch that the major portion of the pressure equalizing medium flowsthrough said ice freezing evaporator, means for supplying liquidrefrigerant to said evaporators, and means for intermittentlydiscontinuing the supply of liquid refrigerant and pressure equalizingmedium to said ice freezing evaporator.

12. That improvement in the art of refrigeration which includes thesteps of supplying refrigerant liquid and a pressure equalizing mediumto an evaporating zone, intermittently collecting the liquid in the pathof supply of the pressure equalizing medium to block fiow thereof by abody of refrigerant liquid and then draining the pressure equalizingmedium flow blocking body of refrigerant liquid into the evaporatingzone.

13. That improvement in the art of refrigeration which includes thesteps of supplying refrigerant liquid and a pressure equalizing me,-dium to an evaporating zone, intermittently increasing the pressure ofthe pressure equalizing medium and introducing a portion of the pressureequalizing medium at the increased pressure into the liquid refrigerantto divert the liquid into the path of the main body of pressureequalizing medium enroute to the evaporating zone, blocking the fiow ofpressure equalizing medium to the evaporating zone by a body of divertedrefrigerant, decreasing the pressure of the pressure equalizing mediumand discontinuing introduction of the pressure equalizing medium intothe refrigerant liquid, and then draining the pressure equalizing mediumfiow blocking body of refrigerant liquid into the evaporating zone.

l4. Refrigerating apparatus comprising an ice freezing evaporator, awater tank in heat transfer relationship with said evaporator at aplurality of points, a chamber refrigerating evaporator, means forsupplying refrigerant to said evaporators, means for supplying pressureequalizing medium to said evaporators at either of two pressures, meansoperated-by pressure equalizing medium at the higher of said twopressures only for conducting liquid refrigerant from said refrigerantsupply means to a storage chamber, and means for controlling saidpressure equalizing medium supply means to supply pressure equalizingmedium at the higher of said two pressures when ice blocks of apredetermined. size have formed in said water tank and to supplypressure equalizing medium at the lower of said two pressures whenpreviously formed ice blocks have melted free of said tank.

15. Refrigerating apparatus comprising an ice freezing evaporator, awater tank in heat transfer relationship with said evaporator at aplurality of points, a chamber refrigerating evaporator, means forsupplying refrigerant to said evaporators, means for supplying pressureequalizing medium to said evaporators at either of two pressures, meansoperated by pressure equalizing medium at the higher of said twopressures only for conducting liquid refrigerant from said refrigerantsupply means into a storage vessel. and means for syphoning refrigerantfrom said storage vessel into said ice freezing evaporator when theliquid level therein reaches a predetermined value, and means forcontrolling said pressure equalizing medium supply means to supplypressure equalizing medium at the higher of said two pressures when iceblocks of a predetermined size have formed in said water tank and tosupply pressure equalizing medium at the lower of said two pressureswhen previously formed ice blocks have melted free of said tank.

16. Absorption refrigerating apparatus comprising a solution circuitincluding a boiler and an absorber, a pressure equalizing medium circuitincluding an evaporator and said absorber, means for liquefyingrefrigerant vapor generated in said boiler, power driven means forcirculating the pressure equalizing medium through its circuit, meansfor heating said boiler, temperature responsive means for controllingthe energization of said power driven means and of said heater, meansfor conveying refrigerant liquid from said liquefying means into saidevaporator,

means responsive to the pressure at which the pressure equalizing mediumis supplied to said evaporator for diverting the refrigerant liquid intothe path of the pressureequalizing medium flowing to said evaporator toblock such flow when such pressure exceeds a predetermined value, meansfor draining the blocking liquid into the evaporator after apredetermined quantity of liquid has accumulated in the path of pressureequalizing medium flow, and means-respom sive to the demand forrefrigeration at said evaporator for regulating the pressure at whichthe pressure equalizing medium is supplied thereto whenever saidcirculator is energized by said first mentioned temperature responsivemeans.

17. Refrigerating apparatus comprising a cooling unit, a water containerin heat transfer relationship with said cooling unit whereby to form abody of ice in said container, means for supplying a cooling medium tosaid cooling unit, and condition responsive means for diverting thecooling medium into a storage vessel in response to a predeterminedcondition to permit said body of ice blocks 'frozen in said container tomelt free of the wall of said container and to float on the surface ofthe contents thereof.

18. Refrigerating apparatus comprising a cool-' ing unit, means forproducing refrigerant liquid, means for circulating a pressureequalizing medium through said cooling 'unit, means for conveyingrefrigerant liquid from said liquid refrigerant producing means to saidcooling unit, and refrigeration demand responsive means forintermittently collecting liquid refrigerant from said conveying meansand for interposing a body of the collected liquid refrigerant in thepath of flow of the pressure equalizing medium to block the flow ofpressure equalizing medium through said cooling unit. I

19. Absorption refrigeration apparatus comprising a boiler, an absorber,a plurality of evaporating elements, a motor operated pump forpropelling a pressure equalizing medium through a circuit including saidabsorber and said evaporating elements, means for liquefying refrigerantvapor generated in the boiler, means for supplying such liquidrefrigerant to one of said evaporating elements, means for drainingunevaporated refrigerant from said one evaporatsel for preventing supplyof pressure equalizing medium to said evaporator when the liquid thereinreaches a predetermined depth, and means for emptying saidcollectingvessel when a predetermined quantity of refrigerant liquid hasbeen collected therein, said apparatus being so constructed and arrangedthat ice blocks will be formed in said container when refrigerant issupplied to said evaporator and previously level and then to drain saidcontainer, and means for circulating an inert gas through saidevaporator.

23. Absorption refrigerating apparatus comprising an evaporator, liquidrefrigerant producing means, means for intermittently discharging apredetermined quantity "of liquid refrigerant into said evaporatorcomprising a container. means for conveying liquid refrigerant from saidproducing means to said container, and a syphon connecting saidcontainer and said evaporator arranged to become operative when theliquid level in said container reaches a predetermined level and then todrain said container, and

the flow of pressure equalizing medium through Y said first mentionedevaporating element, a gas lift pump operated by pressure equalizingmedium supplied from said circuit for diverting liquid refrigerant fromsaid supply means into said blocking device, means for draining liquidrefrigerant from said blocking device into said first mentionedevaporating element, means for supplying electrical energy to saidmotor, a resistance element in series with said motor adapted to reducethe speed thereof to a value medium into said cooling unit, said lastmen-.

tioned means including a collecting vessel, a syphon arranged to emptythe cooling medium collected in said vessel into said cooling unit, andmeans for circulating a pressure equalizing medium through said coolingunit, said circulating means including said collecting vessel and beingarranged to block flow of said pressure equalizing medium by liquidcollected in said collecting vessel. ,7

21. Refrigerating apparatus comprising an evaporator, a water containerin heat exchange relationship therewith, means for supplying pressureequalizing medium and refrigerant liquid to said evaporator, means fordiverting liquid refrigerant from said supply means into a collectingvessel, means within said collecting vesmeans for circulating an inertgas through said evaporator, said container being serially connected tosaid evaporator for flow of inert gas therethrough and arranged to blocksuch" flow when a predetermined quantity of liquid has collectedtherein.

24. That improvement in the art of refrigeration which includes thesteps of continuously generating liquid refrigerant, collecting therefrigerant in a storagerzone, intermittently discharging collectedrefrigerant intoan evaporating zone in heat transfer relationship with abody of material to be frozen at a plurality of freezing zones,evaporating the refrigerant to produce bodies of frozen material, anddiscontinuing the discharge of refrigerant into the evaporating I zonewhile collecting a fresh body thereof to allow the previously frozenbodies to leave the proximity of the evaporating zone.

25. An absorption refrigerating system comprising aninert gas circuitincluding. an evapo- I means to said evaporator, and means in saidliquid refrigerant conducting means for intermittently collecting therefrigerant liquid supplied thereto'to alter the operation of the systemand for, thereafter discharging the collected liquid to allow normaloperation of the system to be resumed, said collecting means beingincluded .in said inert gas circuit, the arrangement being such thatcollection of a predetermined quantity of liquid refrigerant will blockthe flow of inert gas until such collectedliquid is discharged.

v GEO. A. BRACE.

